Second-hand smoke ups risk of abnormal Pap test

NEW YORK (Reuters Health) - Another reason second-hand smoke is bad: there's a chance it can damage the tissues in a woman's cervix, putting her at higher risk for cervical cancer, a new study suggests.

Women smokers have a higher-than-average risk of cervical cancer. The new research did not show that women who inhale other people's smoke are also more likely to end up with that cancer -- but it did show they have a higher risk of having damaged cells in their cervix.

This kind of damage is what doctors look for with Pap tests when they're screening for cervical cancer.

The findings do not prove that second-hand smoke itself is responsible for the cervical abnormalities.

But the results, which came from a study of 4,400 women undergoing Pap tests, do show that "women who report exposure to second-hand smoke are more likely to have an abnormal Pap test than women who do not report exposure to second-hand smoke," said lead researcher Dr. Kristy K. Ward, of the University of California San Diego.

An abnormal Pap test doesn't mean a woman has cervical cancer. In fact, most women with abnormal Pap results do not go on to develop the cancer. But they do need further testing, and sometimes surgery.

The main cause of cervical cancer is persistent infection with certain strains of the human papillomavirus (HPV), which causes genital warts.

It's possible that second-hand smoke makes a woman more vulnerable to developing abnormalities in cervical tissue, according to Ward.

Active smoking has already been linked to an increased risk of cervical cancer, and studies have shown that toxins from both first-hand and second-hand cigarette smoke can be found in cervical tissue.

"In general," Ward told Reuters Health in an email, carcinogens -- the cancer-causing material in tobacco smoke -- "cause the genetic material in the cell to change, so it doesn't function normally. This can lead to abnormalities in the cell that show up on a Pap test and have the potential for progressing to cancer."

Past studies have found a link between second-hand smoke and abnormal Pap results -- but other studies have failed to confirm the connection. This latest study is different in that most of the women involved were Hispanic American.

Hispanic women in the U.S. develop cervical cancer at a rate of 11.5 per 100,000 women -- versus 8 per 100,000 among U.S. women in general.

Of the 4,400 women in this study, about one in every 14 had an abnormal Pap test result.

Overall, the researchers found, women who said they were exposed to "some" second-hand smoke were 70 percent more likely to have an abnormal Pap result than women with no such exposure -- even after other factors, like a woman's own smoking and sexual history, were taken into account.

The results do not specify what the risk of an abnormal Pap smear would be with and without exposure to second-hand smoke. But Ward said any actual increase in risk would be small.

Still, the findings offer yet another potential reason to steer clear of second-hand smoke -- which is already linked to increased risks of asthma and respiratory infections in children, and heart disease and lung cancer in adults.

"Our study once again shows that second-hand smoke exposure is dangerous to a person's health," Ward said.

She also noted that even though most cervical abnormalities on Pap tests will not lead to cancer, at a minimum they lead to extra stress and expenses.

"Personally," Ward said, "a woman with an abnormal Pap test experiences anxiety about the potential of a pre-cancerous or cancerous disease, and it requires extra time, effort and money to continue to return to the health care provider's office for follow-up and treatment."